Newegg, No. 14 in the new 2013 Top 500 Guide, calls the program “Shipped by Newegg.” Merchants on the Newegg Marketplace, which launched in 2010, can sell products to the retailer’s 22 million registered users, Newegg says. Product categories range from clothes to toys to sporting goods to jewelry.

Newegg says its new service can ship 99% of orders within 24 hours of validating payments for those purchases. Sellers that take part in the fulfillment program also receive “special priority” to take part in Newegg merchandising campaigns, but the e-retailer didn’t immediately give details about what that involves.

“We’ve tested our Shipped by Newegg fulfillment service with a few limited sellers and it’s been extremely well received by both customers and businesses,” says Sophia Tsao, head of Newegg Marketplace at Newegg. “Customers can shop with confidence knowing that they can rely on Newegg’s trusted reputation for fast delivery and excellent customer service. Meanwhile, sellers can take advantage of our logistics services so that they can remain focused on growing their businesses.”

Shipping costs vary depending on such factors as package size and whether orders need special handling—for instance, an extra $40 for TVs with screens larger than 42 inches, according to Newegg’s online rate card. For the smallest packages—those no more than 14.25 inches in length, 9.5 inches in width and .75 inches in height, and weighing less than a pound—Newegg charges 95 cents for order handling per order and 95 cents for picking and packing per unit. The program also charges a monthly inventory storage fee of 43 cents per cubic foot from January through September, with that cost increasing to 57 cents from October through December, the holiday shopping season.